// Copyright (c) Lawrence Livermore National Security, LLC and other VisIt
// Project developers.  See the top-level LICENSE file for dates and other
// details.  No copyright assignment is required to contribute to VisIt.

#include <visit-config.h>

#include <cstdio>
#include <cstdlib>
#include <cstring>
#include <ctime>

#include <map>

#if defined(_WIN32)
#include <process.h>
#include <winsock2.h>
#include <windows.h>
#else
#include <unistd.h> // alarm
#include <signal.h> 
#include <sys/types.h>
#include <sys/wait.h>
#include <unistd.h>
#include <sys/socket.h>
#include <netdb.h>
#include <netinet/in.h>
#include <netinet/tcp.h>
#endif

#include <LauncherApplication.h>
#include <ConnectionGroup.h>
#include <FileFunctions.h>
#include <SocketConnection.h>
#include <Utility.h>
#include <vectortypes.h>

#include <DebugStream.h>
#include <IncompatibleVersionException.h>
#include <CouldNotConnectException.h>
#include <LostConnectionException.h>
#include <RPCExecutor.h>

//
// Static member variables.
//
LauncherApplication *LauncherApplication::instance = 0;

// ****************************************************************************
// Method: RPCExecutor<QuitRPC>::Execute
//
// Purpose:
//   Execute a QuitRPC.
//
// Programmer: Brad Whitlock
// Creation:   Fri May 2 17:06:04 PST 2003
//
// Modifications:
//
// ****************************************************************************
template<>
void
RPCExecutor<QuitRPC>::Execute(QuitRPC *quit)
{
    debug2 << "Executing QuitRPC" << endl;
    if (!quit->GetQuit())
        quit->SendError();
    else
        quit->SendReply();
}

// ****************************************************************************
// Method: RPCExecutor<KeepAliveRPC>::Execute
//
// Purpose: 
//   Executes a KeepAliveRPC.
//
// Arguments:
//   keepAlive : A pointer to the KeepAliveRPC object.
//
// Programmer: Brad Whitlock
// Creation:   Fri Mar 12 10:36:46 PDT 2004
//
// Modifications:
//   
// ****************************************************************************

template<>
void
RPCExecutor<KeepAliveRPC>::Execute(KeepAliveRPC *keepAlive)
{
    debug3 << "Executing KeepAliveRPC" << endl;
    keepAlive->SendReply();
}

// ****************************************************************************
// Method: RPCExecutor<LaunchRPC>::Execute
//
// Purpose: 
//   Uses the command line arguments passed from the client to fork a child
//   process that connects back to the client.
//
// Programmer: Brad Whitlock
// Creation:   Mon May 5 09:46:10 PDT 2003
//
// Modifications:
//   
// ****************************************************************************

template<>
void
RPCExecutor<LaunchRPC>::Execute(LaunchRPC *launch)
{
    debug2 << "Executing LaunchRPC" << endl;
    LauncherApplication::Instance()->LaunchProcess(launch->GetLaunchArgs());
    launch->SendReply();
}

// ****************************************************************************
// Method: RPCExecutor<ConnectSimRPC>::Execute
//
// Purpose: 
//   Uses the arguments passed from the client to tell a simulation to connect
//   back to the client.
//
// Programmer: Jeremy Meredith
// Creation:   March 23, 2004
//
// Modifications:
//   
// ****************************************************************************

template<>
void
RPCExecutor<ConnectSimRPC>::Execute(ConnectSimRPC *connect)
{
    debug2 << "Executing ConnectSimRPC"
           << "  Host=" << connect->GetSimHost().c_str()
           << "  Port=" << connect->GetSimPort() << endl;
    LauncherApplication::Instance()->ConnectSimulation(
                                                 connect->GetLaunchArgs(),
                                                 connect->GetSimHost(),
                                                 connect->GetSimPort(),
                                                 connect->GetSimSecurityKey());
    connect->SendReply();
}

// ****************************************************************************
// Method: LauncherApplication::Instance
//
// Purpose: 
//   Creates the one instance of the LauncherApplication object.
//
// Programmer: Brad Whitlock
// Creation:   Fri May 2 17:27:15 PST 2003
//
// Modifications:
//   
// ****************************************************************************

LauncherApplication *
LauncherApplication::Instance()
{
     if(!LauncherApplication::instance)
         LauncherApplication::instance = new LauncherApplication;

     return LauncherApplication::instance;
}

// ****************************************************************************
// Method: LauncherApplication::LauncherApplication
//
// Purpose: 
//   Constructor for the LauncherApplication class.
//
// Programmer: Brad Whitlock
// Creation:   Fri May 2 17:27:46 PST 2003
//
// Modifications:
//   Brad Whitlock, Fri Mar 12 10:37:49 PDT 2004
//   Added new members to handle the KeepAliveRPC.
//
//   Jeremy Meredith, Tue Mar 30 17:27:59 PST 2004
//   Added connectSimExecutor.
//
//   Jeremy Meredith, Thu May 24 11:25:16 EDT 2007
//   Initialize useSSHTunneling.
//
//   Brad Whitlock, Wed Nov 21 11:13:20 PST 2007
//   Added support for forwarding child output.
//
// ****************************************************************************

LauncherApplication::LauncherApplication() : parent(), xfer(), quitRPC(),
    keepAliveRPC(), launcherstate(), childOutput(), launch()
{
    quitExecutor = 0;
    keepAliveExecutor = 0;
    launchExecutor = 0;
    connectSimExecutor = 0;
    timeout = 60;
    keepGoing = true;
    useSSHTunneling = false;
    fixedBufferMode = false;

#if !defined(_WIN32)
    // Set up an alarm signal handler to exit gracefully.
    signal(SIGALRM, LauncherApplication::AlarmHandler);
#endif
}

// ****************************************************************************
// Method: LauncherApplication::~LauncherApplication
//
// Purpose: 
//   Destructor for the LauncherApplication class.
//
// Programmer: Brad Whitlock
// Creation:   Fri May 2 17:28:17 PST 2003
//
// Modifications:
//   Brad Whitlock, Fri Mar 12 10:38:13 PDT 2004
//   Added keepAliveExecutor.
//
//   Jeremy Meredith, Tue Mar 30 17:27:59 PST 2004
//   Added connectSimExecutor.
//
//   Brad Whitlock, Wed Nov 21 11:13:20 PST 2007
//   Added support for forwarding child output.
//
// ****************************************************************************

LauncherApplication::~LauncherApplication()
{
    instance = 0;
    delete quitExecutor;
    delete keepAliveExecutor;
    delete launchExecutor;
    delete connectSimExecutor;

    for(size_t i = 0; i < childOutput.size(); ++i)
        delete childOutput[i];
}

// ****************************************************************************
// Method: LauncherApplication::Execute
//
// Purpose: 
//   Executes the launcher application.
//
// Arguments:
//   argc : The number of command line arguments.
//   argv : The command line arguments.
//
// Programmer: Brad Whitlock
// Creation:   Fri May 2 17:28:42 PST 2003
//
// Modifications:
//   
// ****************************************************************************

void
LauncherApplication::Execute(int *argc, char **argv[])
{
    // Process the command line arguments.
    ProcessArguments(argc, argv);

    // Connect back to the client application.
    Connect(argc, argv);

    // Take care of the application main loop.
    MainLoop();
}

// ****************************************************************************
// Method: LauncherApplication::ProcessArguments
//
// Purpose: 
//   Processes the command line arguments.
//
// Arguments:
//   argc : The number of command line arguments.
//   argv : The command line arguments.
//
// Programmer: Brad Whitlock
// Creation:   Fri May 2 17:29:41 PST 2003
//
// Modifications:
//   Jeremy Meredith, Thu May 24 11:25:31 EDT 2007
//   Added detection of the SSH tunneling argument.  This is how
//   the client tells us the SSH port forwarding is in effect.
//   
// ****************************************************************************

void
LauncherApplication::ProcessArguments(int *argcp, char **argvp[])
{
    int argc = *argcp;
    char **argv = *argvp;

    // Process any relevant command line arguments.
    for(int i = 0; i < argc; ++i)
    {
        std::string arg(argv[i]);
        if(arg == "-timeout" && (i+1) < argc)
        {
            timeout = atol(argv[i+1]);
            ++i;
        }
        else if (arg == "-sshtunneling")
        {
            useSSHTunneling = true;
        }
        else if (arg == "-fixed-buffer-sockets")
        {
            fixedBufferMode = true;
        }
    }
}

// ****************************************************************************
// Method: LauncherApplication::Connect
//
// Purpose: 
//   Connects back to the client process.
//
// Programmer: Brad Whitlock
// Creation:   Fri May 2 17:30:33 PST 2003
//
// Modifications:
//   Brad Whitlock, Tue Jul 29 11:19:26 PDT 2003
//   I changed the interface to ParentProcess::Connect.
//
//   Brad Whitlock, Fri Mar 12 10:39:26 PDT 2004
//   I added the KeepAlive RPC.
//
//   Jeremy Meredith, Tue Mar 30 17:27:59 PST 2004
//   Added connectSimExecutor.
//
//   Brad Whitlock, Wed Nov 21 11:15:42 PST 2007
//   Added another socket to forward output to the client.
//
// ****************************************************************************

void
LauncherApplication::Connect(int *argc, char **argv[])
{
    //
    // Try and connect back to the client.
    //
    TRY
    {
        parent.Connect(1, 2, argc, argv, true);
    }
    CATCH(IncompatibleVersionException)
    {
        debug1 << "The launcher connected to a client that has a different "
               << "version number than the launcher itself."
               << endl;
        RETHROW;
    }
    CATCH(CouldNotConnectException)
    {
        debug1 << "The launcher could not connect to the client." << endl;
        RETHROW;
    }
    ENDTRY

    // Connect the xfer object to the parent process's connections.
    xfer.SetInputConnection(parent.GetWriteConnection());
    xfer.SetOutputConnection(parent.GetReadConnection());

    // Hook up the RPC's to the xfer object.
    xfer.Add(&quitRPC);
    xfer.Add(&keepAliveRPC);
    launcherstate.SetupComponentRPCs(&xfer);

    // Hook up the RPC executors to the RPC's.
    quitExecutor      = new RPCExecutor<QuitRPC>(&quitRPC); 
    keepAliveExecutor = new RPCExecutor<KeepAliveRPC>(&keepAliveRPC); 
    launchExecutor    = new RPCExecutor<LaunchRPC>(&launcherstate.GetLaunchRPC());
    connectSimExecutor= new RPCExecutor<ConnectSimRPC>(&launcherstate.GetConnectSimRPC());
}

// ****************************************************************************
// Method: LauncherApplication::TurnOnAlarm
//
// Purpose: 
//   Turns on an alarm signal to make the application timeout and die.
//
// Programmer: Brad Whitlock
// Creation:   Mon May 5 09:05:35 PDT 2003
//
// Modifications:
//   
// ****************************************************************************

void
LauncherApplication::TurnOnAlarm()
{
#if !defined(_WIN32)
    // Reset the alarm
    alarm(timeout*60);
#endif
}

// ****************************************************************************
// Method: LauncherApplication::TurnOffAlarm
//
// Purpose: 
//   Turns off the alarm signal that will make the application terminate.
//
// Programmer: Brad Whitlock
// Creation:   Mon May 5 09:06:05 PDT 2003
//
// Modifications:
//   
// ****************************************************************************

void
LauncherApplication::TurnOffAlarm()
{
#if !defined(_WIN32)
    // We've got some input.  Turn off the alarm so we can't
    // time out.
    alarm(0);
#endif
}

// ****************************************************************************
// Method: LauncherApplication::AlarmHandler
//
// Purpose: 
//   Handles the alarm signal to terminate the application.
//
// Programmer: Brad Whitlock
// Creation:   Mon May 5 09:06:39 PDT 2003
//
// Modifications:
//   
// ****************************************************************************

void
LauncherApplication::AlarmHandler(int)
{
    debug1 << "Launcher exited due to an inactivity timeout of "
           << LauncherApplication::Instance()->timeout << " minutes." << endl;
    exit(0); // HOOKS_IGNORE
}

// ****************************************************************************
// Method: LauncherApplication::MainLoop
//
// Purpose: 
//   This is the main loop for the launcher application.
//
// Programmer: Brad Whitlock
// Creation:   Fri May 2 17:32:23 PST 2003
//
// Modifications:
//   Brad Whitlock, Wed Nov 21 10:36:01 PST 2007
//   Added support for forwarding child process output to the client.
//
// ****************************************************************************

void
LauncherApplication::MainLoop()
{
    // The application's main loop
    while(keepGoing)
    {
        TurnOnAlarm();

        // Create a connection group that we will use to check if any
        // connections have input to be read.
        ConnectionGroup connGroup;
        connGroup.AddConnection(parent.GetWriteConnection());
#ifndef _WIN32
        for(size_t i = 0; i < childOutput.size(); ++i)
            connGroup.AddConnection(childOutput[i]);
#endif
        // Check the connections for input that needs to be processed.
        if(connGroup.CheckInput())
        {
            if(connGroup.NeedsRead(0))
            {
                TurnOffAlarm();

                TRY
                {
                    // Process input.
                    ProcessInput();

                    // See if we've been told to quit yet.
                    keepGoing &= !quitRPC.GetQuit();
                }
                CATCH(LostConnectionException)
                {
                    // Terminate the application.
                    keepGoing = false;
                }
                ENDTRY
            }
#ifndef _WIN32
            else if(childOutput.size() > 0)
            {
                char         buf[1000 + 1];
                size_t       nbuf = 0;
                std::string *outputs = new std::string[childOutput.size()];
                bool        *valid = new bool[childOutput.size()];

                // Gather all of the output from each child in sequence.
                for(size_t i = 0; i < childOutput.size(); ++i)
                {
                    valid[i] = true;
                    if(connGroup.NeedsRead(i + 1))
                    {
                        debug1 << "Child " << i << " needs to be read (desc="
                               << childOutput[i]->GetDescriptor() << ")" << endl;

                        // Read from the child process's pipe. Note that we use
                        // the read() function because we can't use 
                        // SocketConnection::DirectRead because it calls recv
                        // and that requires a real socket descriptor, whereas
                        // in this case, we have a pipe file descriptor.
                        int nZeroesRead = 0;
                        do
                        {
                            nbuf = read(childOutput[i]->GetDescriptor(), (void*)buf, 1000);

                            if(nbuf > 0)
                            {
                                nZeroesRead = 0;
                                buf[nbuf] = 0;
                                outputs[i] = outputs[i] + std::string(buf);
                            }
                            else
                                ++nZeroesRead;
                        } while(nZeroesRead < 100 && childOutput[i]->NeedsRead(false));

                        // If we read enough zeroes in a row, consider the connection dead.
                        if(nZeroesRead >= 100)
                        {
                            valid[i] = false;
                            debug1 << "Lost connection to child " << i << endl;
                        }
                        else
                            debug1 << "Done reading for child " << i << endl;
                    }
                }

                // Now that we have output from all of the child processes, send it
                // back to the launcher proxy so the client can do something with
                // it.
                std::string completeOutput;
                std::vector<Connection *> validConnections;
                for(size_t i = 0; i < childOutput.size(); ++i)
                {
                    // Append the output to a complete output that we'll send 
                    // to the client.
                    if(outputs[i].size() > 0)
                    {
                        debug5 << "CHILD OUTPUT[" << i << "]: " << outputs[i].c_str() << endl;
                        completeOutput += outputs[i];
                        if(outputs[i][outputs[i].size()-1] != '\n' && (size_t)i < childOutput.size()-1)
                            completeOutput += std::string("\n");
                    }

                    // Delete any child connections that we lost.
                    if(!valid[i])
                        delete childOutput[i];
                    else
                        validConnections.push_back(childOutput[i]);
                }
                childOutput = validConnections;
                delete [] outputs;
                delete [] valid;

                // Forward the output to the client.
                if(completeOutput.size() > 0)
                {
                    debug1 << "Sending " << completeOutput.size() << " bytes" << endl;
                    parent.GetReadConnection(1)->Append(
                        (const unsigned char *)completeOutput.c_str(), 
                        completeOutput.size());
                    parent.GetReadConnection(1)->Flush();
                }
            }
#endif
        }
    }
}

// ****************************************************************************
// Method: LauncherApplication::ProcessInput
//
// Purpose: 
//   Processes input from the client application.
//
// Programmer: Brad Whitlock
// Creation:   Mon May 5 11:00:54 PDT 2003
//
// Modifications:
//   
// ****************************************************************************

bool
LauncherApplication::ProcessInput()
{
    // Try reading input from the parent process's write socket.
    int amountRead = xfer.GetInputConnection()->Fill();

    // Process the new information.
    if(amountRead > 0)
        xfer.Process();

    return (amountRead > 0);
}

// ****************************************************************************
// Method: LauncherApplication::LaunchProcess
//
// Purpose: 
//   Forks and executes a process with the specified arguments.
//
// Arguments:
//   launchArgs : The arguments used to launch the process.
//
// Programmer: Brad Whitlock
// Creation:   Mon May 5 11:23:56 PDT 2003
//
// Modifications:
//   Thomas R. Treadway, Mon Oct  8 13:27:42 PDT 2007
//   Backing out SSH tunneling on Panther (MacOS X 10.3)
//
//   Brad Whitlock, Wed Nov 21 10:30:50 PST 2007
//   I added support for forwarding child process stdout to VCL through a pipe
//   so we can forward that output to the client.
//
//   Brad Whitlock, Mon Apr 27 16:31:23 PST 2009
//   I moved the testing for parallel & engine up to here so I can call
//   SetupGatewaySocketBridgeIfNeeded when I need to connect to simulations.
//
//   Hank Childs, Weds Nov 11 12:05:51 PST 2009
//   Add support for tildes (~). 
//
//   Brad Whitlock, Mon Nov 28 17:04:52 PST 2011
//   I moved the guts to LaunchService.
//
// ****************************************************************************

void
LauncherApplication::LaunchProcess(const stringVector &args)
{
    // Set up an extra indirection if we're tunneling and launching a parallel
    // engine.  SSH port forwarding is typically restricted to forwarding from 
    // localhost which doesn't work if we're on a compute node.
    bool launching_parallel = false;
    bool launching_engine = false;
    for (size_t i=0; i<args.size(); i++)
    {
        if (args[i] == "-np" || args[i] == "-par")
        {
            launching_parallel = true;
        }
        else if (args[i] == "-engine")
        {
            launching_engine = true;
        }
    }
    bool doBridge = useSSHTunneling && launching_parallel && launching_engine;

    SocketConnection *conn = NULL;
    launch.Launch(args, doBridge, &conn);

    // Add the child's output pipe to the list of descriptors that we will check.
    // We add the pipe file descriptor as a SocketConnection object.
    if(conn != NULL)
        childOutput.push_back(conn);
}

// ****************************************************************************
//  Method:  LauncherApplication::ConnectSimulation
//
//  Purpose:
//    Connect to a running simulation
//
//  Arguments:
//    launchArgs   the arguments to be passed to the engine
//    simHost      the hostname of the machine where the simulation is running
//    simPort      the port number where the simulation is listening
//
//  Note:  Much of this code was taken from ParentProcess.  Both should
//         have their socket stuff abstracted into a common location.
//
//  Programmer:  Jeremy Meredith
//  Creation:    March 23, 2004
//
//  Modifications:
//    Jeremy Meredith, Wed May 11 09:04:52 PDT 2005
//    Added security key to simulation connection.
//
//    Hank Childs, Fri Jun  9 15:53:20 PDT 2006
//    Replace sprintf(tmp, "") with strcpy(tmp, "") to remove compiler warning.
//
//    Brad Whitlock, Fri Apr 24 15:21:58 PDT 2009
//    I fixed "parse from ssh_client" for simulations.
//
//    Brad Whitlock, Mon Apr 27 16:31:23 PST 2009
//    I added support for SSH tunnelling.
//
//    Brad Whitlock, Tue Nov 11 21:25:26 PST 2014
//    Added support for fixed buffer sockets needed for BGQ.
//
// ****************************************************************************

void
LauncherApplication::ConnectSimulation(const stringVector &origLaunchArgs,
                                       const std::string &simHost, int simPort,
                                       const std::string &simSecurityKey)
{
    const char *mName = "LauncherApplication::ConnectSimulation: ";
    int                s;
    struct hostent     *hp;
    struct sockaddr_in server;
    stringVector       launchArgs;

    debug1 << mName << "origLaunchArgs={";
    for(size_t i = 0; i < origLaunchArgs.size(); ++i)
        debug1 << origLaunchArgs[i] << " ";
    debug1 << "}" << endl;
    debug1 << "simHost=" << simHost << endl;
    debug1 << "simPort=" << simPort << endl;
    debug1 << "simSecurityKey=" << simSecurityKey << endl;

    //
    // Convert -guesshost to -host XXXX
    //
    for (size_t i=0; i<origLaunchArgs.size(); i++)
    {
        if(origLaunchArgs[i] == "-guesshost")
        {
            // replace -guesshost with -host XXXX
            std::string sshClient;
            if(GetSSHClient(sshClient))
            {
                launchArgs.push_back("-host");
                launchArgs.push_back(sshClient);
            }
        }
        else        
            launchArgs.push_back(origLaunchArgs[i]);
    }

    debug1 << mName << "AFTER -guesshost conversion: launchArgs={";
    for(size_t i = 0; i < launchArgs.size(); ++i)
        debug1 << launchArgs[i] << " ";
    debug1 << "}" << endl;

    // Set up an extra indirection if we're tunneling and 
    // launching a parallel engine.  SSH port forwarding
    // is typically restricted to forwarding from localhost
    // which doesn't work if we're on a compute node.
    if(useSSHTunneling)
        launch.SetupGatewaySocketBridgeIfNeeded(launchArgs);

    debug1 << mName << "AFTER Socket Bridge: launchArgs={";
    for(size_t i = 0; i < launchArgs.size(); ++i)
        debug1 << launchArgs[i] << " ";
    debug1 << "}" << endl;

    //
    // Get the simulation host information
    //
    void *hostInfo = (void *)gethostbyname(simHost.c_str());

    //
    // Set up the structures for opening the sockets.
    //
    hp = (struct hostent *)hostInfo;
    if (hp == NULL)
    {
        EXCEPTION0(CouldNotConnectException);
    }

    memset(&server, 0, sizeof(server));
    memcpy(&(server.sin_addr), hp->h_addr, hp->h_length);
    server.sin_family = hp->h_addrtype;
    server.sin_port = htons(simPort);
    
    // 
    // Create a socket.
    // 
    s = socket(AF_INET, SOCK_STREAM, 0);
    if (s < 0)
    {
        EXCEPTION0(CouldNotConnectException);
    }

    // Disable the Nagle algorithm 
    int opt = 1;
#if defined(_WIN32)
    setsockopt(s, IPPROTO_TCP, TCP_NODELAY, (const char FAR *)&opt, sizeof(int));
#else
    setsockopt(s, IPPROTO_TCP, TCP_NODELAY, &opt, sizeof(int));
#endif

    int success = connect(s, (struct sockaddr *)&server, sizeof(server));
    if (success < 0)
    {
#if defined(_WIN32)
        closesocket(s);
#else
        close(s);
#endif
        EXCEPTION0(CouldNotConnectException);
    }

    //
    // Send the security key and launch information to the simulation
    //
    char tmp[VISIT_SOCKET_BUFFER_SIZE*2];
    int          nleft, nwritten;
    const char      *ptr;

    memset(tmp, 0, sizeof(char) * VISIT_SOCKET_BUFFER_SIZE*2);
    sprintf(tmp, "%s\n", simSecurityKey.c_str());

    ptr = (const char*)tmp;
    nleft = strlen(tmp);
    if(fixedBufferMode)
        nleft = VISIT_SOCKET_BUFFER_SIZE;
    while (nleft > 0)
    {
        if((nwritten = send(s, (const char *)ptr, nleft, 0)) <= 0)
        {
            EXCEPTION0(CouldNotConnectException);
        }

        nleft -= nwritten;
        ptr   += nwritten;
    }

    //
    // Receive a reply
    //
    strcpy(tmp,"");
    char *tbuf = tmp;
    char *tptr = tmp;
    int n;
    char *newline = strstr(tbuf, "\n");
    while (!newline)
    {
        n = recv(s, tptr, VISIT_SOCKET_BUFFER_SIZE, 0);
        tptr += n;
        *tptr = 0;
        newline = strstr(tbuf, "\n");
    }
    *newline = 0;
    if (strcmp(tmp, "success") != 0)
    {
        EXCEPTION0(CouldNotConnectException);
    }

    // Create the Launch args
    memset(tmp, 0, sizeof(char) * VISIT_SOCKET_BUFFER_SIZE*2);
    strcpy(tmp, "");
    for (size_t i=0; i<launchArgs.size(); i++)
    {
        strcat(tmp, launchArgs[i].c_str());
        strcat(tmp, "\n");
    }
    strcat(tmp, "\n");

    // Send it!
    ptr = (const char*)tmp;
    nleft = strlen(tmp);
    if(fixedBufferMode)
        nleft = VISIT_SOCKET_BUFFER_SIZE;
    while (nleft > 0)
    {
        if((nwritten = send(s, (const char *)ptr, nleft, 0)) <= 0)
        {
            EXCEPTION0(CouldNotConnectException);
        }

        nleft -= nwritten;
        ptr   += nwritten;
    }
}
